Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	$ 37,443
Other comprehensive income before reclassifications	7,617
Amounts reclassified from accumulated other comprehensive income	(6,912)
Other Comprehensive Income (Loss), Net of Tax	705	7,869
Total accumulated other comprehensive income, ending balance	38,148
Foreign Currency [Member]
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	1,976
Other comprehensive income before reclassifications	(186)
Amounts reclassified from accumulated other comprehensive income	0
Other Comprehensive Income (Loss), Net of Tax	(186)
Total accumulated other comprehensive income, ending balance	1,790
Unrealized holding gains on available-for-sale securities [Member]
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Total accumulated other comprehensive income, beginning balance	35,467
Other comprehensive income before reclassifications	7,803
Amounts reclassified from accumulated other comprehensive income	(6,912)
Other Comprehensive Income (Loss), Net of Tax	891
Total accumulated other comprehensive income, ending balance	$ 36,358